Vegetarians and vegans are of two minds - no, make that multiple minds - when it comes to imitation meat and dairy products. Some love them and make them a regular part of their meals. Others find them abhorrent, either for health reasons or because they remind them of the very foods they've consciously excluded from their diets.
Others, including me, fall somewhere in between. On the one hand, I enjoy the occasional splurge on a vegan Philly cheesesteak at my favorite restaurant, Tofurkey at Thanksgiving, and a vegan hot dog on the rare occasion I find myself at the local ballpark. On the other, as I never really liked meat and haven't eaten it in 20+ years, I generally dislike any fake meat that tastes too much like "the real thing" (I avoid Boca Burgers, for instance). I'm also concerned about potential hazards of isolated soy protein when consumed in large amounts.
As far as dairy products, I've completely given up on finding a truly vegan cheese that tastes and melts like a dairy version (yes I know about Daiya; I don't like it). We make parmazano (nutritional yeast + almonds) to sprinkle on our homemade pizzas and other foods, but that's about it for cheese substitutes. I never liked drinking cow's milk, so have no problems using soy and almond milk (also homemade) in recipes, cereal, and hot beverages. Frozen bananas blended with these milks make a fine ice cream substitute, and I've had even richer frozen desserts made with nuts or coconut that are just as good as the dairy equivalents.
One really fun recipe I found that makes me feel better about eating vegan hot dogs is the carrot dog from FatFreeVegan. Served on a toasted bun with fixins', I get all the satisfaction of eating a hot dog at a picnic or cookout with friends (or just at home) without any concerns over isolated soy protein or preservatives. I marinate my carrot dogs with Bragg liquid aminos (haven't tried the coconut aminos yet) and apple cider vinegar. (Thanks to my friend Beth for loaning me her camera for the shot at the top of this post!)
Whatever your stance on fake meat, I personally don't see any moral problems with a vegetarian or vegan consuming food that does not come from an animal, even if it looks, smells, and tastes like that animal. It's an individual choice.